Brush-holder for dynamo-electric machines or motors



(No Model.)

F. A. LA ROCHE. BRUSH HOLDER FOR DYNAMO ELECTRIC MACHINES OR MOTORS.

Patented Apr. 15, 1890.

U ITED "STATES.

PATENT OFFICE.

FREDRICK A. LAROOIIE, or PHILADELPHIA, PENNSYLVANIA.

BRUSH-HOLDER FOR DYNAMO-ELECTRIC MACHINES oR Mo'ToRs.

SPECIFICATION forming .part of Letters Patent No. 425,435, dated April"15, 1890.

Application filed December -'7, 1389. Serial No. 382,984. (No nib'delo"To aZ Z whom, it may concern: I life 1t known that I, FREDRIOK A.LARocHE, a citizen of the United States, and a resident of the city ofPhiladelphia and State of Pennsylvania, have invented a new and useful1mproveincnt in Brush-Holders for Dynamos or Motors, of which thefollowing is a clear and sufiicient specification, reference being hadto the drawings annexed.

My invention relates principally to brushholders intended to be usedwith carbon or ,other rigid or inelastic brushes, but can be used withadvantage also with other brushes now in-use.

In the present form of-brush-holders the brush is held without anyprovision for lateral adjustment except the elasticity of the brushitself. On this account the brushes are usually made of thin strips ofcopper or other elastic conductor, as carbon or other rigid brushes, thoigh used, required an extremely careful adjustment to make an even,contact between the commutator and the brush, because if they do notlie fiat against the commutator, and thus make an even contact, thecommutator wears unevenly and the machine sparks; To make an evencontact and to enable the brush to lie automatically flat against thecommutator is the object of my invention, which consists, essentially,in

'making the clamp holding the brush automatically adjustable, as will benow more particularly described.

Figure 1 shows an end View of a brushholder containing my invention andthe adjacent parts of a dynamo. Fig. 2 is a side View of a partof abrush-holder containing my invention. Fig. 3 shows the brush andcommutator, the dotted lines showing the various positions in which thebrush might be. Fig. 4: is a sketch of a modification of my invention.

' I attach to the frame of a dynamo or motor of any common type abrush-holder, which I have shown in Fig. 1, of the common adjustableform as to the supporting portions,which consist, as shown, of therocker-arms B B, "1-

brating on the spindle U, to which it may be clamped at'any desiredangle by the set-screw D, and having backwardly-extending spindlesEE,;on which are placed the yokes F F,

i that are impelled inwardly by the tensionsprings G G. These parts,however,are allwell known, and form no limitationupon my invention,whichimay be applied to the supporting port-ion of any form ofbrush-holder. To this portion of a clamp I, in which I secure ,thebrush, so as to allow a free oscillatory movement of the-latter in thedirection of its width. practice by pivotingthe clamp to the yoke F,preferably, though not necessarily, at a right angle with therocker-arm, by a pivot or equivalent device. A modification is shown inFig. 4, in which the desired automatic adjustability of the brush-holderis obtained by attaching the clamp holding the brush to suggest itselfto a workman skilled in the art-as, for instance, by fastening it (seeFig. 4). to a fastened 'to the spindle E of abrush-holder. Thisspring Hcan take the-place of the tension-spring G, accomplish the same resultsas the pivot shown in Fig. the brush K, which I generally make of apiece of carbon. The advantages of the use of this material arewellknown, but have not hitherto been made much use of on account of thedifli culty of adjusting it in the ordinary rigid brush-holder, causedby its inelasticity. I do not, however, limit myself to a brush ofcarbon, as the advantages of my invention extend equally to a. brush ofa rigid-piece of copper or other conducting material;=or, if desired,the ordinary brush can be inserted.

It can readily be seen that a brushplaced in a brush-holder having anoscillating motion, as above described, will adjust itself sobrnsh-holder (tothe yoke B, as shown in my illustrations) I attach theThis I effect in 7 v spring H, the other end of which I have shown whileits sidewise oscillations 3. .In this clamp I is secured as to lie fiatagainst and make an even contact with the commutator if placed in any ofi the positions shown by the dotted lines in Fig. 3, and will be aidedto fall into position.

by the rotation of the commutator, and'that though it is preferable thatthe clamp osci'l-- late substantially in a plane parallel to the axis ofthe commutator and be placed directly opposite the latter very largevariations can be made without interfering with the capacity of thebrush-holder to allow the brush to. adjust itself and to make an evencontact with the commutator.

I operate my machine as follows: In the commutator, and do this even ifthe level of: m

clamp I, I secure the brushes K K, which, if they are made of carbon orother rigid material, I preferably make extend far enough out from theclamps to bring the flat portion into contact with the commutator iftheir ends are rough. I then start the machine. The brushes immediatelyadjust themselves, so that there is no sparking or wearing of the thelatter is not perfect,either through wear or defective construction. v

What I claim, and desire to secure by Letters Patent, is-

1. The combination, with the commutator and frame-work of a dynamo ormotor, of a rigid brush lying in a plane tangent to the commutator-and abrush-holder attached to 4 said frame-work and freely and automati--cally movable in two intersecting planes, substantially as described.

2. The combination, with the commutator and frame-work of a dynamoor'motor, of a rigid brush lying in a plane parallel toa plane tangentto the surface. of the commutator,-a brush-holder freely andautomatically movable in two intersecting planes, and

u a spring impelling the brush down on the commutator, substantially asand for the purpose set forth.

3. The combination of the commutator and I frame-work 0i a dynamo ormotor with a brush-holder consisting of a supporting-piece attached tosaid frame-work, freely and antomatically movable in a planesubstantially perpendicular to the axis of the commutator, and aclamping piece attached to said supporting-piece, freely andautomatically movable in a plane substantially parallel to the axis ofthe commutator, substantially as and for the purpose set forth. 4. Thecombination, with the commutator ,andframe-work ot a dynamo or motor, ofthe supporting portion of a brush-holder, freely rigid brush lyingwholly in a. plane parallel to a plane tangent to the surface of thecommutator and a brush-holder freely and automaticall-y. movable both ina plane substantially at right angles with the commutatorshaft and in aplane substantially parallel to the surface of the commutator,substantially as and for the purpose set forth.

. FREDRICK A. LAROCHE.

lvitnessesi MARK WILKS COLLET, GEO. H. Rarson.

